When police arrived at the apartment, where her three young children were present, the woman began talking about the burglary calmly but then allegedly suddenly came at officers with a knife yelling "you ready? Motherf---s," according to an audio recording of the incident released by the Seattle Police Department.

"Get back! Get back!" the officers responded before opening fire on Lyles, while at least one child can be heard crying in the background.

"The officers immediately performed first aid while the Seattle Fire Department responded, but the fire department declared the woman deceased once they arrived,” according to a police statement. "There were several children inside the apartment at the time of the shooting, but they were not injured."

“How is it possible that a woman who called the police for help ended up dead?”

Family members say Lyles was three months pregnant, and long struggled with mental illness, according to the Seattle Times.

She was “tiny” and had "mental health problems," Lyles' sister Monika Williams told the Seattle Times.

“Why couldn’t they have Tased her? They could have taken her down. I could have taken her down,” she told the newspaper, noting that Lyles' children witnessed her shooting.

In the audio recording, the officers are heard talking about Lyles as someone who has said "weird statements" and has a "safety caution."

Williams said she believes race was a factor in the officer’s decision. Lyles was black and the two officers were white, according to authorities.

Seattle Police Detective Mark Jamieson said Lyles had a recent “encounter” with police, who have been called to her apartment several times before — a history that warranted the dispatch of two officers rather than one.

Seattle police respond at the scene where police earlier shot and killed a woman while responding to a burglary call.KING5

“Although this was a typical burglary report, two officers were required due to information pertaining to this address that presented an increased risk to officers," Jamieson said in a statement.

One of the officers was an 11-year veteran while the other was "newer" he said.

Both have been placed on administrative leave pending an investigation, he said.

The apartment complex where Lyles was living with her children is for "formerly homeless individuals and families" and operated by Solid Ground, a non-profit which combats poverty in the Seattle area, said Mike Buchman, a spokesman for the organization.

Buchman said the complex "has never had a police shooting" and the incident "far outstrips anything" they've ever seen.

Seattle Mayor Ed Murray called the incident a "tragedy for all involved" and vowed there would be a full investigation into the matter in a statement.

"Our historic police reforms, from de-escalation training to civilian-monitored force review, are in place to address such crises," he said. "The quality and integrity of the investigation will be reviewed by the federal monitoring team supervising our consent decree. We will work collectively with our consent decree partners and the Community Police Commission to ensure transparency throughout this process and offer support where needed,” he said.

The Seattle Police Department had a long history of using excessive force against people with mental illness and substance abuse problems, prompting a Department of Justice investigation which resulted in a "consent decree" in 2012 — meaning the federal government would oversee some of their policies and practices.

Candles and flowers form an impromptu memorial to Charleena Lyles in Seattle.KING5

"The investigation found that SPD officers escalate situations, and use unnecessary or excessive force, when arresting individuals for minor offenses. This trend is pronounced in encounters with persons with mental illnesses or those under the influence of alcohol or drugs. This is problematic because SPD estimates that 70 percent of use of force encounters involve these populations,” according to the DOJ report.

But a federal monitor overseeing the court-ordered reforms found the department made significant strides in training and conduct since the consent decree five years ago, according to a report released in April.

“Overall use of force has gone down even as officer injuries have not gone up and crime, by most measures, has not increased. At the same time, the force that SPD officers do use is, by and large, reasonable, necessary, proportional, and consistent with the Department’s use of force policy, “ the report said.

But community activists say they are not convinced.

"What police are touting as improvements, we rebuke," said Gerald Hankerson, president of the NAACP of Seattle-King County. "If you ask the black community, things are just as bad today as they were before the consent decree so what it the point of even having one," he said.

"How is it possible that a woman who called the police for help ended up dead?" he said.

Others added that the police department still has a long way to go.

"It is clear that the ‘historic reforms’ within the Seattle police department, a department with a long record of racially discriminatory violence, have fallen far short of what was needed to keep Lyles and her family safe, " said Kristin Rowe-Finkbeiner, a Seattle resident and the executive director of the nonprofit group MomsRising, in a statement.

Several community members and family came together at a vigil honoring Lyles on Sunday night. Loved ones brought photos and flowers in her memory.

Williams set up a GoFundMe page, which has already garnered over $30,000 as of Monday afternoon, to raise money for Lyles' children who are now left without a mother.

“Please help us come together to support her children and family during this tragedy,” she said on the page with includes the hashtags #SAYHERNAME and #LEENABOOMATTERS.